Now is the time to plant spring flowering bulbs. I was reminded of this while touring the gardens this month at Hillwood Museum and Gardens.

Bill Johnson, horticulturist for the garden, said its tulips are planted late in the season because they are less susceptible then to problems from squirrels and disease. Hillwood treats bulbs as annuals.

Garden centers still have stock; you can also buy online. In this region, bulbs usually can be planted into December. Soil temperatures are well above the 45 to 50 degrees Fahrenheit that many spring bulbs require to feel at home and begin growing roots.

The primary food source for a bulb is its widened tuberous growth, so when buying bulbs, bigger is better. Roots produce the foliage and flowers. All true bulbs need are good drainage and the right temperatures. They already have the stem, bud and flower parts inside, formed and all set to go. The food supplies were produced last season as the foliage grew in full sun.

Tulips are the only bulbs that don't produce enough food from natural means and need supplemental feeding. They like a balanced fertilizer, such as 9-9-6 Bulb Booster or equivalent material spread at a rate of two pounds per hundred square feet. It can be incorporated into the planting hole or mixed into the soil when tilling.

I use the term "bulb" loosely, as many horticulturists do, to refer to a variety of plants with specialized roots for storing food. But all thick or fleshy rooted plants aren't true bulbs. They could actually be corms, rhizomes, tubers or bulbs depending on their physiology. A true bulb consists of a leaf or flower bud encased in food storage layers called scales.

From a design standpoint, corms, rhizomes and tubers, such as gladiolus, cannas and dahlias, respectively, can all be considered in the same general category, but most of the major spring bloomers are true bulbs. Plant several different species and you can coordinate blooming times so that fall-planted, spring-flowering bulbs can open from February to July.

Plant bulbs in forests, fields, flower beds and containers. If possible, keep containers in a protected area until mid-March. Trees overhead won't rob sunlight from seasoned early spring flowering bulbs, but if flowers are going to return annually, bulbs need a minimum of six hours of sunlight a day after flowering to season. "Season" means the leaves grow for several weeks, turn brown or yellow and produce and store enough food for next year.

The earliest spring-flowering bulbs emerge through the snow, such as snowdrops and glory-of-the-snow (Chionodoxa). Winter aconites (Eranthis) are welcome golden yellow flowers, blooming on bare ground in February, sometimes January. These tubers that are members of the buttercup family are effective near your entry or window to view from indoors. Bluebells, also called scilla, flower at about the same time as winter aconites but are taller. The blue clusters of flowers are outstanding framed by snow.

Fertilize bulb beds naturally by coating the soil surface with bone meal, cottonseed meal and hardwood ashes from the fireplace. Spread each one at a rate of 5 to 10 pounds per 100 square feet and then dig it in with your composted organic material. You can find bone and cottonseed meal at your local garden center.

A landscape design with bulbs is most effective when the flowers are installed in drifts or waves of the same color. Always buy multiples of eight to 10 or more of each variety. A hundred is usually 10 times better. If you like to mix colors that all bloom at the same time, sprinkle them evenly for the best effect.

There are specialized bulb planting tools that push straight down into the soil and remove a plug at the proper depth. The Bulb Hound is an innovative and well-designed planter. It's built like a mini-post hole digger, with a heavy-duty steel jaw that punches the hole. When you pull it out, there's a lever on the handle that opens it to release the soil and quickly backfill the hole. It digs down to six inches and ensures that the same varieties of bulbs are planted at equal depths. There are other short- and long-handled bulb planters, but this is the only one with a jaw that opens to release soil, and it carries a lifetime guarantee. Visit their Web site at www.hound-dog.com or call 800-694-6863.

If you prefer electric planting, there are augers that fit on a half-inch electric drill. They are sold at garden or home improvement centers. Hold the drill firmly with two hands. Do not lean on it as if you're drilling iron. In case the auger hooks into a root, it helps if the drill has reverse.

Use bulb size as a depth gauge. If a tulip is two inches high, plant it six inches deep. For corms and true bulbs, place the pointed side up and the flatter side down. Water when planting. Don't over water. Bulbs don't like wet feet.

Here is some more information on spring-flowering bulbs that can be planted now:

* Snowdrops (Galanthus). These white flowering bulbs will be the easiest to grow and fastest to naturalize and fill an area, even in your woodland garden.

* Glory-of-the-snow (Chionodoxa). The brilliant blue flowers that appear around the same time as snowdrops have six to 10 flowers on each plant. For best results, plant these true bulbs in full eastern sun with afternoon shade. Also a good lawn bulb and available in white, pink or blue.

* Crocuses. These small, early-blooming corms can be planted in mixed colors. I prefer grouping the same varieties together and like to use a hybrid that has a multi-colored flower, such as Crocus crysanthus "Blue Pearl" with soft blue flowers and a bronzy-yellow base. Crocuses come in of purple, blue, yellow or white. They will naturalize to come back for many years.

* Crown Imperial (Fritillaria). The yellow, orange, white or checkered-colored flowers from May into June are striking. The bulb is planted on its side at a depth of three times its width. They're repugnant enough to be a repellent to moles, voles, rabbits and other critters. Flowering stems can be up to three feet tall. Try an American native, Fritillaria affinis "Vancouver Island"; it has burgundy-brown drooping bell-shaped flowers on 10- to 12-inch stems.

* Daffodils (Narcissus). To me, this is the first official sign that the growing season has begun, the flower that marks the commencement of myriad subterranean processes. Daffodils happen to be early risers and are not eaten by any mammal. There is such a variety of types that you can plant only daffodils and coordinate them to bloom from February to July. You simply need to choose early-, medium- and late-blooming varieties. Many will naturalize into a field or woodland, and you can look forward to enjoying daffodils for many years.

Local garden centers are a drive away. To order by mail, a couple of sources are Brent and Becky's Bulbs at 877-661-2852 (www.brentandbeckysbulbs.com) or Dutch Gardens at 888-821-0448 (www.dutchgardens.com).

For a comprehensive reference book, "Bulbs," by John Bryan (Timber Press, 2002, $89.95), is a 524-page tome that will provide you with everything you ever wanted to know about bulbs.

Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site, www.gardenlerner.com.

Tulips require special care with fertilizer.Snowdrops are among the

earliest flowering bulbs.Early daffodils can signal

spring's approach.A honeybee visits a crocus on

a February day.